Just about finished replacing wood in the transom and two stringers. I am going to finish the Bilge with Bilgecoat. What can I use over the epoxy resin as a light filler that I can sand easily prior to painting. Am I correct in that a polyester filler like used in auto body is not compatible with Epoxy?

No I would never use any Bondo type filler ,How much do you have to fill? I would use something from West, like a 407 or a 410 filler mixed with any left over epoxy to smooth and fair any fabric edges or texture and give a sanding base..

Interlux & awlgrip also make epoxy based fairing fillers.. They are stronger & shrink less than th polyester based stuff.. We use them in our shop, or we blend our own..

If you want to blend your own with the epoxy resin there are additives that you can blend doing different things. Some additives just thicken the resin, others thicken but allow for more adhesive strength. There are also others that thicken and fill but offer easier sanding for fairing..

Hope this helps.. Jamie / Lakeside

Ultra Fair by Adtech is great stuff for use with epoxy.

ADTECH 861 ULTRA FAIR FAIRING COMPOUND - Marine 861 UltraFair is a convenient trowelable filler developed for fairing large surface imperfections on aluminum, steel, fiberglass or wooden marine vessels. With the cold weather hardener it is easier to mix-apply-cure during colder weather conditions. The white resin and brown hardener, when mixed together at the convenient 1:1 volumetric mix ratio, yield a smooth, creamy paste which can be easily applied up to 1" thick without sagging or shrinking during the curing process. 861 UltraFair Resin and Hardener are 100% solids systems and may be used above or below the waterline. When cured, this system features excellent sanding and finishing characteristics and accepts virtually all types of primers and paints. Sold by the 2 gallon kit (makes 4 gallons total.)

I dont need to fill alot. Basically to level out where the stringers are glassed to the transom, and to level out the glass so its doesent show the pattern through the paint. I have a West Marine nearby thats probably what Ill use, I was looking for something that sanded easier than the Epoxy. Thanks .

West systems epoxy with 410 filler sands really easy and goes fast either by hand or DA. Even the 404 bedding filler sands fine in my experience. Sometimes I mix 410 and 404 around corners where I want a bit of strength.

Thanks The 410 sanded very easy and feathers good.